A contractive method for computing the stationary solution of the euler equation

A contractive method for computing stationary solutions of intertemporal equilibrium models is provide. The method is is implemented using a contraction mapping derived from the first-order conditions. The deterministic dynamic programming problem is used to illustrate the method. Some numerical examples are performed.

Evaluating the existence of structural change in the brazilian term structure of interest: evidence based on cointegration models with structural break

This paper investigates whether there is evidence of structural change in the Brazilian term structure of interest rates. Multivariate cointegration techniques are used to verify this evidence. Two econometrics models are estimated. The rst one is a Vector Autoregressive Model with Error Correction Mechanism (VECM) with smooth transition in the deterministic coe¢ cients (Ripatti and Saikkonen [25]). The second one is a VECM with abrupt structural change formulated by Hansen [13]. Two datasets were analysed. The rst one contains a nominal interest rate with maturity up to three years. The second data set focuses on maturity up to one year. The rst data set focuses on a sample period from 1995 to 2010 and the second from 1998 to 2010. The frequency is monthly. The estimated models suggest the existence of structural change in the Brazilian term structure. It was possible to document the existence of multiple regimes using both techniques for both databases. The risk premium for di¤erent spreads varied considerably during the earliest period of both samples and seemed to converge to stable and lower values at the end of the sample period. Long-term risk premiums seemed to converge to inter-national standards, although the Brazilian term structure is still subject to liquidity problems for longer maturities.

Multiple equilibria and protectionism

In a nonnative approach, I analyze trade policies when the industrial sector genentes positive extemalities in production, and there are adjustments costs to changing production from one sector to the other. Protectionist trade policy can make workers intemalize the benetits from moving into the industrial sector, but it is a second best policy as it also causes consumption distortions. I show that if the govemment is able to fully commit to its tariff schedule for the future, the welfare maximizing policy is to maintain a positive tariff forever, even after all adjustment has already taken place . However, if the govemment is not able to commit at all, the only time consistent policy is zero tariff at any point in time. The time inconsistency of the full commitment policy is derived from the fact that in the model only production needs interference, and the production distortion is lagged one period with respect to the tariff wbile the consumption distortion is simultaneous to the tariff. In the intermediary case, i.e., when the government can commit for a limited period of time, the time consistent optimal tariff will be positive but lower than the "full commitment" tariff. This result indicates that some institutions that have always been considered pure sources of inefficiency, such as protectionist lobbying, may in fact be welfare improving in some cases!

Tree-structured smooth transition models

The goal of this paper is to introduce a class of tree-structured models that combines aspects of regression trees and smooth transition regression models. The model is called the Smooth Transition Regression Tree (STR-Tree). The main idea relies on specifying a multiple-regime parametric model through a tree-growing procedure with smooth transitions among different regimes. Decisions about splits are entirely based on a sequence of Lagrange Multiplier (LM) tests of hypotheses.

Factors affecting the technical efficiency of production of the Brazilian banking system : a comparison of four statistical models in the context of data envelopment analysis

This paper uses an output oriented Data Envelopment Analysis (DEA) measure of technical efficiency to assess the technical efficiencies of the Brazilian banking system. Four approaches to estimation are compared in order to assess the significance of factors affecting inefficiency. These are nonparametric Analysis of Covariance, maximum likelihood using a family of exponential distributions, maximum likelihood using a family of truncated normal distributions, and the normal Tobit model. The sole focus of the paper is on a combined measure of output and the data analyzed refers to the year 2001. The factors of interest in the analysis and likely to affect efficiency are bank nature (multiple and commercial), bank type (credit, business, bursary and retail), bank size (large, medium, small and micro), bank control (private and public), bank origin (domestic and foreign), and non-performing loans. The latter is a measure of bank risk. All quantitative variables, including non-performing loans, are measured on a per employee basis. The best fits to the data are provided by the exponential family and the nonparametric Analysis of Covariance. The significance of a factor however varies according to the model fit although it can be said that there is some agreements between the best models. A highly significant association in all models fitted is observed only for nonperforming loans. The nonparametric Analysis of Covariance is more consistent with the inefficiency median responses observed for the qualitative factors. The findings of the analysis reinforce the significant association of the level of bank inefficiency, measured by DEA residuals, with the risk of bank failure.

A conditional likelihood ratio test for structural models

This paper develops a general method for constructing similar tests based on the conditional distribution of nonpivotal statistics in a simultaneous equations model with normal errors and known reducedform covariance matrix. The test based on the likelihood ratio statistic is particularly simple and has good power properties. When identification is strong, the power curve of this conditional likelihood ratio test is essentially equal to the power envelope for similar tests. Monte Carlo simulations also suggest that this test dominates the Anderson- Rubin test and the score test. Dropping the restrictive assumption of disturbances normally distributed with known covariance matrix, approximate conditional tests are found that behave well in small samples even when identification is weak.

Uma análise de incentivos contratuais em arranjos de parceria de atendimento ao cidadão

Com base em proposições depreendidas da teoria da economia dos custos de transação, da teoria dos incentivos e dos contratos incompletos, esta pesquisa realiza um estudo de casos múltiplos buscando encontrar correspondentes empíricos para tais formulações. O foco dessa dissertação está em uma oportunidade incomum: a ocorrência simultânea de dois diferentes modelos de parceria com sistemas de incentivos distintos aplicados ao mesmo serviço. O Poupatempo e a Unidade de Atendimento Integrado - UAI, dois importantes programas regionais brasileiros de atendimento presencial ao cidadão, que possuem objetivos semelhantes e que empregaram recentemente diferentes modelos de parceria. Enquanto São Paulo utilizou da terceirização para expandir o Poupatempo desde 2007, Minas Gerais desenvolveu o UAI desde 2011 com uma parceria público-privada. Este estudo de casos múltiplos desenvolve-se com base em uma análise contratual que identifica os incentivos formais das parcerias aliada a avaliação dos resultados dos agentes privados com base nos relatórios de desempenho. Para além da análise destes documentos, entrevistas semiestruturadas nos permitem analisar as variáveis não-contratuais. Assim, os elementos extraídos dos dois casos nos permitem observar os pressupostos depreendidos das três teorias.

On theory multiple contraction

The one which is considered the standard model of theory change was presented in [AGM85] and is known as the AGM model. In particular, that paper introduced the class of partial meet contractions. In subsequent works several alternative constructive models for that same class of functions were presented, e.g.: safe/kernel contractions ([AM85, Han94]), system of spheres-based contractions ([Gro88]) and epistemic entrenchment-based contractions ([G ar88, GM88]). Besides, several generalizations of such model were investigated. In that regard we emphasise the presentation of models which accounted for contractions by sets of sentences rather than only by a single sentence, i.e. multiple contractions. However, until now, only two of the above mentioned models have been generalized in the sense of addressing the case of contractions by sets of sentences: The partial meet multiple contractions were presented in [Han89, FH94], while the kernel multiple contractions were introduced in [FSS03]. In this thesis we propose two new constructive models of multiple contraction functions, namely the system of spheres-based and the epistemic entrenchment-based multiple contractions which generalize the models of system of spheres-based and of epistemic entrenchment-based contractions, respectively, to the case of contractions (of theories) by sets of sentences. Furthermore, analogously to what is the case in what concerns the corresponding classes of contraction functions by one single sentence, those two classes are identical and constitute a subclass of the class of partial meet multiple contractions. Additionally, and as the rst step of the procedure that is here followed to obtain an adequate de nition for the system of spheres-based multiple contractions, we present a possible worlds semantics for the partial meet multiple contractions analogous to the one proposed in [Gro88] for the partial meet contractions (by one single sentence). Finally, we present yet an axiomatic characterization for the new class(es) of multiple contraction functions that are here introduced.

Modelos matemáticos para estimativa do consumo máximo de oxigênio pela ventilometria de esforço em indivíduos saudáveis

The relation between metabolic demand and maximal oxygen consumption during exercise have been investigated in different areas of knowledge. In the health field, the determination of maximal oxygen consumption (VO2max) is considered a method to classify the level of physical fitness or the risk of cardiocirculatory diseases. The accuracy to obtain data provides a better evaluation of functional responses and allows a reduction in the error margin at the moment of risk classification, as well as, at the moment of determination of aerobic exercise work load. In Brasil, the use of respirometry associated to ergometric test became an opition in the cardiorespiratory evaluation. This equipment allows predictions concerning the oxyredutase process, making it possible to identify physiological responses to physical effort as the respiratory threshold. This thesis focused in the development of mathematical models developed by multiple regression validated by the stepwise method, aiming to predict the VO2max based on respiratory responses to physical effort. The sample was composed of a ramdom sample of 181 healthy individuals, men and women, that were randomized to two groups: regression group and cross validation group (GV). The voluntiars were submitted to a incremental treadmill test; objetiving to determinate of the second respiratory threshold (LVII) and the Peak VO2max. Using the método forward addition method 11 models of VO2max prediction in trendmill were developded. No significative differences were found between the VO2max meansured and the predicted by models when they were compared using ANOVA One-Way and the Post Hoc test of Turkey. We concluded that the developed mathematical models allow a prediction of the VO2max of healthy young individuals based on the LVII

Short-term temporal changes of bare soil CO2 fluxes after tillage described by first-order decay models

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Genetic parameters for milk yield analyzed by test-day models in Murrah buffaloes in Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Atividade do professor na educação a distância: interações com o gênero profissional docente

This research aimed to analyze the dynamics established between the activity of the teacher in Distance Education (DE) and professional gender of teaching, in terms of impact of DE in teacher s usual professional activity. Previous studies showed that one of the central discussions concerning DE refers to the role that the teacher is called to perform. The present research, based on theoretical and methodological assumptions issued from Clinic of Activity, analyzed the impact referred above. This central aim was operationally executed along three main stages: 1) survey study for description of socio-professional profile of teachers working in DE in two universities from Natal (RN-Brazil), 2) clinical analysis of professional activity of teachers working in DE, taking into account four simultaneous levels of psychological constitution and development of human activity: personal, interpersonal, transpersonal and impersonal; 3) analytical focus on transpersonal context in order to understand the influence of pedagogical practice in DE on professional gender of teaching. Documental research, audio recorded voice data and a multiple choice Likert scale questionnaire concerning socio-professional information were used as procedural tools. The qualitative-clinical procedural tool of instruction to the double , firstly proposed by Clinic of Activity research group, was used in order to obtain oral productions concerning professional activity. Data issued from stage 1 (n=70, 28 men and 41 women) was submitted to descriptive and inferential statistical analyzes. 65.7% of the sample worked in a public institution, 30% in a private institution, and 4.3% in public and private institutions. 31.4% of the sample of participants was formed by teachers having a master degree, 28.6% were doctors and 26.3% had degrees of specialists. 54.3% of participants acted as remote tutor, and 44.3% were regents teachers. After descriptive multidimensional cluster analysis, two groups emerged (remote tutors and regents teachers), the most important variables in terms of contributions to this distinction being: professional function, level of graduate formation, level of income, activities and forms of entry in DE. Clinical analysis of data produced by two participant-teachers of each group, issued from instruction to the double technique, was performed. This analysis indicated the existence of different models of distance education. A general concern referring to the need of both taking into account information technology and pedagogical attitudes was detected. On the other hand, participant-teachers considered that participation in DE activities could bring relevant contributions to general professional gender of teaching. . Finally, teachers warned against certain formats of organization of teachers professional activity, as found in the domain of DE, since these activities could promote the intensification and individualization of teachers` work activity, and even the worsening of relations, rather than exchanges and shares through collective bargaining. This process could compromise the renew of the professional gender, by losing its historical roots and diminishing activity possibilities of teachers in their labor context

Análise preditiva da densidade mineral óssea em adolescentes brasileiros eutróficos do sexo masculino

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Photoelastic Analysis of Biomechanical Behavior of Single and Multiple Fixed Partial Prostheses With Different Prosthetic Connections

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Finite Element Stress Analysis of Edentulous Mandibles with Different Bone Types Supporting Multiple-Implant Superstructures

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)